git.add().addFilepattern(file).call();
git.commit().setMessage("commit").call();
DirCache index = db.lockDirCache();
DirCacheBuilder builder = index.builder();
builder.add(createEntry(file, FileMode.REGULAR_FILE, 1, ""));
builder.add(createEntry(file, FileMode.REGULAR_FILE, 2, ""));
builder.add(createEntry(file, FileMode.REGULAR_FILE, 3, ""));
builder.add(createEntry("b.txt", FileMode.REGULAR_FILE));
assertTrue(builder.commit());